What you will learn
Select and verify measurement principles; wire and diagnose 4-20 mA loops; use HART; calibrate transmitters and RTD/thermocouple inputs.
Course syllabus
- 1. Measurement principles
Pressure and level · Temperature and flow
- 2. Signals
4-20 mA loops and HART
- 3. Calibration
Calibration and documentation
- 4. Troubleshooting
Signal troubleshooting method
Free lesson · 18m
Pressure and level
Pressure measurement covers gauge, absolute and differential. The distinction matters: a gauge transmitter referenced to atmosphere reads differently from an absolute transmitter, and using the wrong type produces a consistent offset that looks like a calibration error.
Hydrostatic level measurement uses differential pressure and depends on the density of the fluid. If the actual density differs from the design density, the level reading is wrong even though the transmitter is perfectly calibrated. This is one of the most common apparent instrument faults that is actually a process condition.
For closed vessels, wet and dry leg arrangements change the calculation. Always read the installation detail before concluding a level transmitter is faulty.
Gauge, absolute and differential are not interchangeable; hydrostatic level depends on density; wet and dry legs change the calculation.